Multi-channel high pressure swivel

ABSTRACT

A multi-channel swivel with the wear capability of rigid hard seal means by providing a single mandrel and multiple outer bodies to allow each body to have one or more seals inserted into one or both ends of each body, thereby allowing for three or more seal paths in the swivel.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Patent application titled “FLUID SWIVEL WITH COOLING PORTING” filed on the same date.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] N/A

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISK

[0003] N/A

BACKGROUND OF THE INVENTION

[0004] The field of this invention is that of multi-port hydraulic swivels for the purpose of communicating high pressure liquids or gasses from a non-rotating location to a rotating location. The most common application is on the central shaft of a hose reel in which the central shaft of the reel rotates with the drum. The drum will be rotating as the hose is rolled out to its intended service. The pressure fluid supply to the reel will characteristically not be rotating, and therefore a rotating union will be required between the non-rotating fluid supply and the rotating main shaft of a reel drum.

[0005] The importance of this type swivel has greatly increased as the drilling of oil and gas wells has moved to deep offshore waters. Drilling contemporarily occurs in 8,000 to 10,000 feet of seawater. In lowering the drilling system to these depths and in lowering certain completion and testing equipment, continuous pressure contact is desired to be maintained between the surface and the subsea equipment being lowered and/or operated. In some cases operational pressure is required as the equipment is lowered. In other cases, maintaining pressure on the system is a safety consideration. If the operator releases the pressure, the hose will become disconnected from the heavy package being lowered and allow the hose to be recovered. This is especially important if the heavy package becomes stuck on lodged in deep water.

[0006] As greater depths are encountered and higher pressures are desired to be maintained as the reel and swivel are rotated. This higher pressure and the inherently higher number of rotations associated with deeper water depth cause specific problems with the swivels.

[0007] A first problem is that a high degree of wear tends to occur in soft seals which can be inserted into machined grooves in the inner or outer surface of the mating parts. If a harder seal can be utilized at the higher pressures, a better or more extended wear life can be provided. An opposing pair of seals can be installed in the end of the outer body to a stopping shoulder and followed by a threaded gland to act as the opposing shoulder. On the other end of the outer body a second set of seals can be inserted to the opposite side of the central shoulder and again followed by a gland. This configuration can be utilized for a single or dual channel swivel, but there are needs for triple and quadruple channel swivels which cannot be serviced in this manner as there are only two ends to the outer body.

[0008] A second problem is that the higher pressure and higher number of rotations generates heat. Heat generated on the outside of the seals disperses into the outer body which has progressively greater area as the distance moves away from the seals, and has a relatively large outer surface to dissipate the heat to the environment. The heat generated at the I.D. of the seal moves toward the centerline of the mandrel portion of the swivel, and literally runs into the heat generated on the opposite of the mandrel. The heat has no place to go, so it builds up to higher temperatures. The higher temperatures characteristically increase the friction, generating more heat at an even faster rate. In some cases we have seen, the heat gets so high in contemporary applications that the seals are actually cooked and fail.

BRIEF SUMMARY OF THE INVENTION

[0009] The object of this invention is to provide a multi-channel swivel which will allow for three or more channels with seals of a material which must be inserted into the end of the bore rather than being bent to allow insertion into a groove in the bore of the Outer Body or into a groove on the Mandrel.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

[0010]FIG. 1 is a partial section thru a subsea blowout preventer stack and a view of a reel in which a swivel of this invention would be used.

[0011]FIG. 2 is a schematic showing how a swivel of this invention is used.

[0012]FIG. 3 is a half section of a swivel of this invention.

DETAILED DESCRIPTION OF THE INVENTION

[0013] Referring now to FIG. 1, a blowout preventer (BOP) stack 10 is landed on a subsea wellhead system 11, which is supported above mudline 12. The BOP stack 10 is comprised of a wellhead connector 14 which is typically hydraulically locked to the subsea wellhead system 11, multiple ram type blowout preventers 15 and 16, an annular blowout preventer 17 and an upper mandrel 18. A riser connector 19, and a riser 20 to the surface are attached for communicating drilling fluids to and from the surface.

[0014] Reel 30 has a frame 31, spool 32, and a swivel 33 mounted on the central shaft of the spool (not shown). Hose and/or cable reel 34 is shown going from the spool 32 of the reel 30 to a control box 35 on the subsea blowout preventer stack 10. From the control box 35, appropriate hoses 37 go to control various functions, such as ram blowout preventer 16.

[0015] Referring now to FIG. 2, a reel schematic is shown. Spool 32 is shown mounted on the central shaft 50 which is supported by conventional bearings (not shown). On the left end of the central shaft 50 is mounted a swivel 51 having an outer body 52 and a mandrel 53. connection 54 attaches the swivel 33 to central shaft 50.

[0016] Hydraulic lines 60-63 are attached to the swivel outer body 52 to deliver pressurized fluids to the swivel from the non-rotating hydraulic supply (not shown). Within the spool, line 70 connects with line 60 and exits the main shaft 50 and goes directly to the hose bundle 80 going to the ocean floor. This line is characteristic of the lines which need the pressure to be maintained during the rotating operations. Gage 81 is provided on this line to monitor the pressure in this line. Line 71 connects with line 61 and also goes directly to the hose bundle and is characteristic of a return line which would not require the high pressure during rotation. Line 72 and 73 connect with lines 62 and 63 respectively and supply a multi-valve panel 82 on the side 83 of the spool 32 for individual control of a multiplicity of lines to subsea equipment.

[0017] Stab Plate 84 engages receptacle plate 85 to give individual hydraulic supply to various selected lines when the reel is not rotating. Control box 86 provides for operational control of the spool 32, failsafe brakes 87 provide stopping power for the spool 32, locking pin 88 provides positive position stopping for the spool 32, and motor 89 provides operations power for the spool 32 thru chain 90.

[0018] Referring now to FIG. 3, a half section of the swivel of this invention can be seen. Inner mounting plate 100 is attached to the main shaft 50 by bolts 101. Outer mounting plate 102 is mounted to the mandrel 103 by bolts 104. Outer mounting plate 102 is attached to the inner mounting plate 100 by bolts 105.

[0019] Mandrel 103 is an cylindrical member with 8 seal surfaces 110-117 and locating shoulders 120 and 121. Fluid pressure communicates thru port 130, thru seal sub 131, drilled hole 132, and out port 133. Similar flow paths occur in ports 134, 135 and 136 at 90 degree spacings around the mandrel 103.

[0020] Body 140 provides a central locating shoulder 141, and end thread 143 which engaged by a gland 144, and an end thread 145 which is engaged by gland 146. The space between the central locating shoulder 141 and the glands 144 and 146 provides cavities for the insertion of seals 150 and 151 on one end and 152 and 153 on the other end. This provides that when high pressure is in the area between these seals, the outward force is directed by an appropriate shoulder or gland to resist the force. By providing the threaded gland design, seals made of hard plastic like material are able to be installed to give superior wear life in comparison to the life afforded by softer seals which can be stretched into grooves.

[0021] Similarly, Body 160 provides a central locating shoulder 161, and end thread 163 which is engaged by a gland 164, and an end thread 165 which is engaged by gland 166. The space between the central locating shoulder 161 and the glands 164 and 166 provides cavities for the insertion of seals 170 and 171 on one end and 172 and 173 on the other end. This provides that when high pressure is in the area between these seals, the outward force is directed by an appropriate shoulder or gland to resist the force.

[0022] The shoulder is indicated in the preferred embodiment to be a threaded gland. In practicality, lock rings, bolted flanges, and other style shoulder means can be used to achieve the goal of retaining the seals within the cavity. Literally, the end of the other body can provide the means to retain the seal within the cavity.

[0023] In this way each of 2 bodies has provided a central shoulder and a gland on each end to trap 2 sets of seals each, for a total of 4 sealed ports. The mandrel 103 has been made from a single piece of metal and provides a straight continuous flow path for the porting. The outer body is not continuous but is rather made of 2 independent bodies 140 and 160. Mating shoulders 180 and 181 keep the bodies 140 and 160 accurately aligned and bolts 182 keep them attached together for rotary operation. In this way we can install four sets (pairs) of seals which are not amenable to deforming and insertion into grooves. This allows a single swivel to have 3, 4, or more channels of high pressure service.

[0024] Port 190 is an air inlet port which can be used to flow air thru port 191 to allow for cooling of the mandrel 103 of the swivel. Ports 200-204 provide for leak detection from the seals. Thread 210 provides for an anti-rotation means to stop the rotation of the bodies while the mandrel is being rotated.

[0025] In this way swivels with 3, 4, 5 or even more fluid channels can be provided.

[0026] The foregoing disclosure and description of this invention are illustrative and explanatory thereof, and various changes in the size, shape, and materials as well as the details of the illustrated construction may be made without departing from the spirit of the invention. 

I claim:
 1. A swivel comprising a mandrel with two or more fluid passages communicating between an end and the exterior surface of said mandrel, two or more bodies surrounding said mandrel, at least two of said bodies having a recess on at least one end for receiving seals.
 2. The invention of claim 1, wherein said two or more of bodies having at least one seal retention ring proximate the end of said body after said seals are inserted.
 3. The invention of claim 1 wherein said two or more bodies are attached together to act as a single unit.
 4. The invention of claim 1 wherein said two or more bodies are threaded together to act as a single unit.
 5. The invention of claim 2 wherein said seal retention ring is a threaded gland.
 6. The invention of claim 2 wherein said seal retention ring in one of said two or more bodies is retained by the position of one of the other of said one or more bodies.
 7. The invention of claim 1 wherein one of said bodies has and internal surface and another of said one or more bodies has an external surface to engage said internal surface for axial alignment of the first of said bodies to the second of said bodies.
 8. A fluid communication rotary swivel providing the wear capability of utilizing seal rings for the communication of multiple channels of fluid comprising, a mandrel with three or more fluid paths communicating from one or more ends to the external surface of said mandrel, two or more bodies surrounding said mandrel with at least one end of said two or more of bodies having at least one seal inserted into the end of said outer bodies and having at least one seal retention ring proximate the end of said body after said at least one seal is inserted.
 9. The invention of claim 8 wherein said two or more bodies are attached together to act as a single unit.
 10. The invention of claim 8 wherein said two or more bodies are threaded together to act as a single unit.
 11. The invention of claim 8 wherein said seal retention ring is a threaded gland.
 12. The invention of claim 8 wherein said seal retention ring in one of said two or more bodies is retained by the position of one of the other of said one or more bodies.
 13. The invention of claim 8 wherein one of said bodies has and internal surface and another of said one or more bodies has an external surface to engage said internal surface for axial alignment of said first body to said second body.
 14. In a reel for handling one or more hoses from an offshore floating facility such as a drilling vessel or a service vessel to subsea drilling or service equipment, a swivel comprising a mandrel with two or more fluid passages communicating between an end and the exterior surface of said mandrel, two or more bodies surrounding said mandrel, said bodies having a recess on at least one end for receiving seals.
 15. The invention of claim 14, wherein said two or more of bodies having at least one seal retention ring proximate the end of said body after said seals are inserted.
 16. The invention of claim 14 wherein said two or more bodies are attached together to act as a single unit.
 17. The invention of claim 14 wherein said two or more bodies are threaded together to act as a single unit.
 18. The invention of claim 15 wherein said seal retention ring is a threaded gland.
 19. The invention of claim 15 wherein said seal retention ring in one of said two or more bodies is retained by the position of one of the other of said one or more bodies.
 20. The invention of claim 14 wherein one of said bodies has and internal surface and another of said one or more bodies has an external surface to engage said internal surface for axial alignment of the first of said bodies to the second of said bodies. 